Hi
1. Temp was 5 at noon and dropped 59 degrees at midnight. 5+(-59)= -54 (B)
2. The stock dropped by 5 points and opened at 93 points that day.
93+(-5)=88 points (B)
3. The temperature fell by 12° over 4 hours.
12÷4=3° decreased per hour (C)
Hope that clarifies these. Let me know if these aren't clear.